diff --git a/cd.sh b/cd.sh
index 020f5fe..583d97d 100644
--- a/cd.sh
+++ b/cd.sh
@@ -1,15 +1,27 @@
-echo "\
-nameserver 9.9.9.9
-" > '/etc/resolv.conf' \
-&& \
+NAMESERVERS=(
+'9.9.9.9'
+)
+PACKAGES=(
+'git'
+)
+REPOSITORY='rwx.work/cd'
+TARGET='/usr/local/sbin'
+
+for nameserver in "${NAMESERVERS[@]}" ; do
+    echo "nameserver ${nameserver}" \
+    >> '/etc/resolv.conf' \
+    || exit
+done
+
 apt-get update \
-&& \
-apt-get install \
-'git' \
---yes \
-&& \
+|| exit
+
+apt-get install --yes "${PACKAGES[@]}" \
+|| exit
+
 git clone \
-"${GITHUB_SERVER_URL}/rwx.work/cd" \
-'/usr/local/sbin' \
-&& \
+"${GITHUB_SERVER_URL}/${REPOSITORY}" \
+"${TARGET}" \
+|| exit
+
 cd-bootstrap.sh